The ARPANET IMP Port Expander
A 1980 technical report on the ARPANET Interface Message Processor port expander, prepared by SRI International's Computer Science and Technology Division for the US Defense Technical Information Center and its readers. The pictures are plain line diagrams: boxes labelled IMP and COMPUTER joined by thick connecting lines, a hexagonal ARPANET network map, a front panel with circles and rectangular indicators, and a port expander linking computers to a gateway and nodes, useful to a designer wanting schematic network-diagram vocabulary.
